Striking machine

ABSTRACT

The striking machine has a hammer which repeatedly strikes an anvil to drive a tool connected thereto. The hammer is spring biased to the striking position and the hammer is raised against the spring bias by a linkage from the hammer member to a rotary cam. As the cam is rotated the hammer is raised and continued rotation of the cam provides for a lost motion wherein the hammer is released from the cam and the spring forces the hammer to strike the anvil.

United States Patent 1 1 1 11 3,747,691 Lundman et a]. July 24, 1973 STRIKING MACHINE 1,464,824 8/1923 Kollock et al. 173 119 2,772,858 12/1956 Galuez 173/119 [761 Sigurd Lundmanolasatan 3,587,754 6/1971 Laatsch 173/119 82; Karl Aston Nilsson, Hasqegaton both of 94020 ojebyn Sweden Primary Examiner-James A. Leppink [22] Filed: Feb. 9, 1971 Attorney-Darby & Darby [2]] Appl. No.: 113,889

[57] ABSTRACT [30] Foreign Application Priority Data The striking machine has a hammer which repeatedly Feb. 13, 1970 Sweden 1851/70 Strikes to drive a connected thereto- The hammer is spring biased to the striking position and the 52 U.S. C1. 173/119, 173/124 hammer is raised against the Spring bias y a linkage s 1 1m, c1..; B25d 1/00 from the hammer member to a rotary As the cam 53 Field Search 173/1 19 123, 124 is rotated the hammer is raised and continued rotation of the cam provides for a lost motion wherein the ham- 5 References Cited mer is released from the cam and the spring forces the I UNITED STATES PATENTS hammer to strike the anvil. 2,298,792 10/1942 Hicks 173/119 4 Claims, 2 Drawing Figures PATEN-IE JUL 2 4 i975 SHEET 2 [1F 2 FIG.2

STRIKING MACHINE This invention relates to a striking machine comprising a tool holder and a striking mechanism adapted by a hammer member to effect repeated blows against an anvil mounted in connection to the tool holder.

Striking machines of the aforesaid kind are previously known and available in many different constructions. The mechanisms utilized in these machines for effecting the striking movement, and thereby the impact proper, are relatively expensive and, consequen'tly, also the purchase price of the machines is high.

The present invention, therefore, has as its object to produce a striking machine of the aforesaid kind which comprises a simplified but safely operating mechanism for effecting the striking movement, and which is cheap to manufacture. The machine according to the invention is particularly adapted for driving in sheet pilings and the like, for breaking frozen soil, concrete and the like, and is to be designed such that it can be mounted on the bucket of an excavator. The striking machine according to the invention, of course, shall also be adapted for use for the same purpose and in the same way as known machines of this kind. These objects of the invention are achieved in that the striking machine is characterized in that the striking mechanism comprises a mechanism for moving the hammer member a suitable distance from the anvil, and a striker spring coacting with the hammer member and adapted during the movement of the hammer member to be compressed so as upon spring-back to effect the blow of the hammer member against the anvil.

The invention is described in the following in greater detail, with reference to the accompanying drawings showing by way of example an embodiment of the invention.

FIG. 1 shows in a section a front view of the machine according to the invention, and

FIG. 2 shows a lateral view, also in a section, of the machine in FIG. 1.

In the drawings, 1 designates generally that machine portion in which at the embodiment shown the drive motor of the machine is disposed. It may, however, be pointed out already here, that the necessary driving power can be supplied to the machine in other known ways, so that the machine need not carry any drive motor. The motor applied in the embodiment shown which may be electric, hydraulic, pneumatic or an internal combustion engine, is connected via a suitable transmission (not shown) with a drive shaft 3 supported in a bearing 2. Said bearing 2 is mounted in a partition wall between the motor part 1 and a casing 4, which includes the mechanism of the machine for effecting the striking movement required. Said mechanism hereinafter will be called lifting mechanism.

A disc 5, which is connected to or integral with the drive shaft 3, is provided with a number of holders 6 for example four holders as shown in the drawings which may be welded on orin another way secured on the disc 5, for mounting thereon a cam plate 7 suitably spaced from said disc. The mounting proper of said plate 7 preferably is made by means of screws 8 rendering it possible to exchange the cam plate, when necessary, easily and rapidly.

The cam plate 7 is formed inwardly with a cam curve 9, which may be said to have Z-shape and is symmetric in relation to a plane through the narrowest curve per tion, i.e., said cam curve in the embodiment shown comprises two identical lift curves, which during one revolution effect two blows. It is also possible to form the cam plate with only one such curve or with more than two curves, depending on how many blows per minute at a definite speed of the drive shaft 3 are desired.

With said cam plate 7,7 or more precisely with its cam curve 9, coacts a cam follower in the form of a lift pin 10 mounted for rotary motion in a bearing 11. Said bearing 11 is secured at one end of an arm 12, which is pivotally supported on an axle 13 and with its other end, in the starting position shown in the figures, abuts a mounting sleeve 15 suspended from the axle 13 for mounting therein a hammer member, which is a lift rod 16 with a striking head 17. The lift: rod 16 is rigidly connected with the mounting sleeve: by means of cotter pins, studs, screws 18 or the like. Guide bars 19 are arranged on both sides of the axle 13 for guiding the axle so as to move in a straight line without deflecting laterally along a lift line, which in the embodiment shown coincides with the longitudinal axis of the lift rod and is laterally offset in relation to the center of rotation of the cam plate.

For guiding the lift rod 16, a guide sleeve 20 is provided in spaced relationship to the axle 13, which sleeve at its ends is provided with suitable slide bearings for the lift rod. The guide sleeve 20 is supported on a plate 21, which is fastened by bolts between the casing 4 for the lifting mechanism and a. casing 22 enclosing the striking mechanism proper, at the end of which casing 22 a tool holder 23 with anvil 24 is arranged. Between the striking head 17 of the lift rod and the plate 21 a strong striker spring 25 enclosing the lift rod 16 is clamped, which spring upon lifting of the lift rod is compressed still more so as upon spring-back to effect the blow. The striking machine according to the invention operates as follows. In the starting position shown in the drawings the striking head 17 abuts the anvil 24 by action of the striker spring 25, and one lift curve of the cam curve is located with its lowermost portion below the pin 10, spaced therefrom as shown in FIG. 2. After said lowermost portion the lift curve ascends relatively flatly to a lift pocket 26. Each of the lift curves, more precisely, is designed so as during one third of a revolution to effect one quarter of the total lifting movement, while it during the following one sixth of the revolution effects the remaining part of the lifting movement, provided that the cam curve comprises two identical cam curves.

Subsequent to the coupling-in of the drive shaft 3, thus, the cam plate 7 is turned and the first lift curve is caused to engage with the lift pin 10 onthe pivotal arm 12, which pin thereby can roll on the cam surface, and then said curve lifts the lift pin 10 and thereby the pivotal arm 12, the axle .13 and the lift rod 16 relatively slowly until the lift pocket 26 has caught the pin 10,

whereafter the remaining part of the lifting operation takes place very rapidly. The lifting movement is interrupted when the angle between the surface of the lift pocket 26 on which the pin rests and the lift line, designated in FIG. 1 by 27, exceeds At this moment the pin 10, by action of the highly tensioned strikerspring 25, rolls off from the lift curve and at the same time the arm 12 is pivoted back to the position shown in the figures. The striker spring now rapidly moves the striking head against the anvil 24 for carrying out the blow proper.

When the lift pin is rolling off from the lift curve, the arm 12 is pivoted vehemently in counter-clockwise direction and abuts the lift rod 16 or, more precisely, the mounting sleeve thereof. For reducing the effect of the arm impact against the sleeve, a shock-absorbing cushion 28 is fastened at the end of the arm. The cushion has as a further object to limit the pivotal movement of the arm in counter-clockwise direction, so that v the lift pin 10 at the striking movement is guided to the lowermost portion of the lift curve, which does not participate in the lifting carried out, and which now is turned ahead through half a revolution in relation to the position shown in the figures. During the following half revolution performed by the drive shaft the aforedescribed machine cycle is repeated, i.e., with a cam plate according to the embodiment shown two blows per revolution are effected, but by replacing this cam plate by a cam plate having one or, for example, three lift curves, the conditions can be changed and adjusted to the demand and application field in question.

What we claim is:

1. A striking machine comprising:

a. a striking member;

b. means for biasing said striking member;

c. one end of said striking member being rotatably secured to an axle, said axle being restrained in its travel to a direction along the longitudinal axis of said striking member;

d. a lever member, said lever member being rotatably mounted to said axle at a point between the ends of said lever;

e. a pin projecting outwardly from one end of said lever;

f. an interior camming surface, said surface when rotated periodically engaging and releasing said pin; and

g. means for preventing said second end of said lever from passing the longitudinal axis of said striking member.

2. The apparatus of claim 1 wherein said means for preventing said second end of said lever comprises a mounting sleeve on said striking member.

3. The apparatus of claim 2 wherein said second end of said lever comprises a resilient material.

4. The apparatus of claim 1 wherein said interior camming surface comprises at least two identical curves each of said curvesdefining a trailing lifting pocket and a leading edge said curves being disposed so that when said trailing pocket of said first curve is substantially in line with the longitudinal axis of said striking hammer said leading edge surface of said second curve is not substantially aligned with said longitudinal axis of said striking hammer whereby said pin falls from said lifting pocket of said first curve to the lowest point of said second curve without striking said leading surface of said second curve as said lifting pocket of said first curve passes the longitudinal axis of said striking hammer. 

1. A striking machine comprising: a. a striking member; b. means for biasing said striking member; c. one end of said striking member being rotatably secured to an axle, said axle being restrained in its travel to a direction along the longitudinal axis of said striking member; d. a lever member, said lever member being rotatably mounted to said axle at a point between the ends of said lever; e. a pin projecting outwardly from one end of said lever; f. an interior camming surface, said surface when rotated periodically engaging and releasing said pin; and g. means for preventing said second end of said lever from passing the longitudinal axis of said striking member.
 2. The apparatus of claim 1 wherein said means for preventing said second end of said lever comprises a mounting sleeve on said striking member.
 3. The apparatus of claim 2 wherein said second end of said lever comprises a resilient material.
 4. The apparatus of claim 1 wherein said interior camming surface comprises at least two identical curves each of said curves defining a trailing lifting pocket and a leading edge said curves being disposed so that when said trailing pocket of said first curve is substantially in line with the longitudinal axis of said striking hammer said leading edge surface of said second curve is not substantially aligned with said longitudinal axis of said striking hammer whereby said pin falls from said lifting pocket of said first curve to the lowest point of said second curve without striking said leading surface of said second curve as said lifting pocket of said first curve passes the longitudinal axis of said striking hammer. 